This invention relates to a hose with an intermediate coupling such as a brake hose with an intermediate coupling.
For example, a brake hose with an intermediate coupling includes: a coupling portion; a cylindrical sleeve extending from at least one end of the coupling portion; a hose inserted into the sleeve; and a substantially cylindrical nipple inserted into a center hole of the hose at a position corresponding to the sleeve. The sleeve is fastened to the hose while caulked in the radial direction and thereby interposing the hose with the nipple. The thus obtained brake hose with an intermediate coupling is used with the coupling portion thereof being fixed to the body of a motor vehicle by a bolt or the like.
In such an intermediate coupling, the outer diameter of the nipple is generally set to a value substantially equal to the inner diameter of the hose to facilitate the insertion of the nipple into the center hole of the hose. However, if this makes the nipple held by the hose with a gap interposed therebetween, it is difficult to obtain a sufficient fastening force even after the sleeve has been caulked in the radial direction. As a result, a high pressure applied to the oil within the hose may displace the nipple from the position corresponding to the sleeve, causing the nipple to move within the hose. In this case, if the nipple comes off the coupling portion and sleeve, the hose moves within the sleeve along the length of the sleeve, and such movement of the hose may interfere with other parts fixed to the body of the motor vehicle.
To overcome this problem, the outer surface of the nipple has been grooved so that the area of contact of the nipple with the hose can be increased to permit simple insertion of the nipple into the hose with a comparatively satisfactory fastening force (Japanese Utility Model Unexamined Publication Sho-55-31025, Japanese Patent Postexamined Publication Hei-3-15066).
However, even if the outer surface of the nipple is grooved, the nipple may, in some cases, move, although only slightly, within the hose from a regular position corresponding to the sleeve depending on the positions at which the sleeve is caulked in the radial direction.